Liquid crystal displays (LCDs) are a kind of flat panel display device that utilizes liquid crystals to display images. Because of their advantages over other display devices such as lighter weight, thinner profile, lower driving voltage and lower power consumption, the LCDs have found wide application in the industries. However, because liquid crystal panels of the LCDs are unable to emit light by themselves, a light source device such as a backlight device must be provided in each of the LCDs.
In use of a backlight device currently available, a remarkable temperature rise can be found near the light source. The temperature rise not only degrades the light emission efficiency of the light source, but also leads to a nonuniform temperature distribution in the LCD which uses the light source to provide back light. The higher temperature of the LCD near the light source also leads to a reddish color, which has an adverse effect on the imaging quality of the liquid crystal panel. Moreover, the temperature rise of the light source also shortens the service life of the light source itself significantly.